Magnetic tape cartridges which are compliant to the LTO (Linear Tape Open) standard have been widely used for the data backup media of computer system. The construction of the magnetic tape cartridge (abbreviated as “a cartridge”, hereinafter) is that a magnetic tape reel (abbreviated as “a reel”, hereinafter) which can rotate to wind or feed out the magnetic tape wound therearound is set in the cartridge and the rotation is locked by a reel lock and unlocked by a release pad when the cartridge is unloaded from and loaded to a backup drive unit, respectively. This mechanism supports the unexpected rotation of the reel so that the magnetic tape is not jammed up in the cartridge. Both reel lock and the release pad are installed in a center room formed in the reel.
The FIG. 8A shows a zoom up cross sectional view of the reel lock and the release pad. FIG. 8A specifically shows the assembly of the cartridge when it is loaded to the backup drive for operation and therefore the reel is unlocked. The reel driving mechanism D pushes up the release pad 500 by which the reel lock 300 is pushed up to be released from the locking fins 202 by making a space between the locking fins 202 and the corrugation surface 303. When the reel driving mechanism D rotates the reel 200, then the release pad 500 rotates in conjunction with the reel 200 since the release pad is engaged with the reel 200 in the inner drum 201. A projection 301 that has a round head formed in the center portion on the downward surface of the reel lock 300 is pushed in contact against a contact surface 501 formed in the center portion of the upward surface of the release pad 500. The reel lock 300 is pushed against the release pad 500 by a compressive coil spring 400.
The projection 301 of the reel 300 is abraded in contact with the contact surface 501 of the release pad 500, by which the projection 301 may be worn out eccentrically to the rotation axis. The cause of this problem is due to lack of impartial spring force against the upward surface of the reel lock 300 and the physical fact such that there is no stable contact point between the round head of the project 301 and the plane surface at the contact surface 501 when the projection 301 and the contact surface 501 are pushed therebetween. As the result of the eccentric worn out of the projection, the reel lock 300 becomes unparallel to the release pad 500 or the bottom surface of the inner drum 201 as shown in FIG. 8B. Then the peripheral portion 302 of the reel lock 300 may touch the locking fins 202 formed in the inner drum 201 of the reel 200 and generate a noisy sound. To prevent the generation of the noisy sound, a conventional technology has been proposed in a patent in the reference 1where a metal plate attached onto the top of the contact surface 501 so that the wear out is reduced, which means the time until the wear out can be extended. Therefore it is possible to keep long time before such noise starts to be generated. The locking fins 202 are to seize the reel lock 300 at the corrugation surface 303 formed on the downward surface of the reel lock 300 so that the reel latched to stop.
Reference 1
Published Japanese Patent Application: Paragraph 0016and the FIG. 5, JP, 2002-197833, A (2003)